In both fixed wing and rotor aircraft, deicing is an ongoing technical challenge.
Current fixed wing aircraft utilize various methods to prevent ice formation on wing and engine inlet surfaces. These methods include pneumatic, electrostatic, and thermal systems. Not all of these methods are applicable to every surface and ice formation continues to be a problem. This can result in ice breaking off and damaging the aircraft (i.e., ice formation on projections in engine inlets can lead to engine fan blade damage when accumulated ice becomes detached and goes down the inlet). In the worst cases, pilot and passenger safety is compromised.
Current rotor aircraft UH-60 Black Hawk and AH-64A Apache utilize electro-thermal systems to remove ice where blade leading edges are heated by wires embedded in the leading edge composite under a titanium wear strip. Problems such as wire burn out, and controller failure can lead to leading edge overheating, causing damage to composites and blade delamination. Leading edge damage from excessive heat has been a problem with the Apache AH-64A. Because of unreliability and demanding power requirements, the system is often not used or permanently disabled, and the UH-60 Black Hawk operators manual states that blade de-ice operation with system installed may cause blade damage.
At present, ground or air de-icing causes mission delays and missed forecasts. Actual in-flight icing causes mission cancellations and abortions. The Army Safety Office data indicates that icing problems occur often and likely cause millions of dollars in damage and loss of life.
Other methods which have been used or tested have specific limitations and caveats. These methods include the Pneumatic Boot (requires increased torque), Fluid Anti-icing System (limited amount of fluid & use time because of weight).
In a related application, submarine periscope window fouling is also an ongoing problem.